This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. We prepared thin slices of rat heart tissue (~50 microns thick), freeze dried and placed into an ultralene thin film tissue holder. The sample were irradiated at 12 keV for purposes of detect the elemental content distribution and determine the Zn content for spectroscopy purposes. These experiments evaluated the efficacy of this method with this sort of tissue and tissue preparation. We found that the method can detect enough amount of Zn to allow performing XANES at Zn K edge with sufficient effectiveness. This experiment also allowed us to collect preliminary data that will be used to plan next experiments.